IN NAWA, AFGHANISTAN When Gen. David H. Petraeus makes his case that the military's strategy in Afghanistan is succeeding, he cites the evolution of this community of mud-walled homes and wheat fields:

June 2009: In the throes of the Taliban. A few dozen British soldiers holed up inside a small base in the center of Nawa. Nightly gun and grenade fights. Schools and markets closed. Residents terrorized.

The following 17 months: A 1,000-strong surge battalion of U.S. Marines arrives July 2009. Focuses on protecting the civilian population. American and British advisers build local government. Tens of millions of dollars are pumped in to fund reconstruction projects.

Today: One of the safest districts in southern Afghanistan. Marines who live at former British base have not fired a single bullet while on foot patrol in the past five months. Classrooms packed. Bazaar thriving.

To Petraeus, the top U.S. and NATO commander in Afghanistan, what has occurred here validates his contention that a comprehensive counterinsurgency strategy can reverse Taliban momentum and stabilize Afghanistan after years of downward drift. In presentations to senior members of President Obama's national security team who are participating in an evaluation of the war, he has displayed a PowerPoint slide titled, "Nawa: Proof of COIN [counterinsurgency] Concept."

"We started achieving progress with security, then governance, and then citizen confidence - that's literally how it plays out," Petraeus said in a recent interview at his headquarters in Kabul. "It's the kind of progression we're trying to achieve in other areas."

It is undeniable that Nawa has undergone a remarkable transformation since the Marines swept in, and it represents what is possible in Afghanistan when everything comes together correctly. But five visits by this reporter since July 2009 suggest that the changes in this district are fragile and that much of what has transpired here is unique rather than universal.

"Nawa is not like the rest of Afghanistan," said district governor Abdul Manaf. "It is a great success because many things have happened here that have not happened in other places."

The ratio of troops, both American and Afghan, to the population is higher than in most places. The Afghan army battalion that is partnered with the Marine battalion here has greater experience than many other units in the area. And unlike the vast majority of districts, the contingents of Afghan soldiers and policemen are at full strength.

On the civilian side, Nawa is blessed with a far more harmonious relationship among its tribes than most other districts; Manaf is regarded by U.S. and Afghan officials as an unusually competent governor; and the U.S. Agency for International Development has poured in more money here, per capita, for reconstruction and short-term employment projects than any other part of the country.

Many civilian officials who track the war at the White House, the State Department and the CIA remain unconvinced that other parts of Afghanistan will turn around as quickly as Nawa has. They argue that weak local governance, tribal rivalries, inept development projects and incompetent Afghan security forces remain the norm.